Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Jack Morgenstein <jackm@dev.mellanox.co.il>,
        Leon Romanovsky <leonro@mellanox.com>,
        Jason Gunthorpe <jgg@mellanox.com>
Subject: [PATCH 5.2 224/313] RDMA: Fix double-free in srq creation error flow
Date:   Thu,  3 Oct 2019 17:53:22 +0200
Message-Id: <20191003154555.095265867@linuxfoundation.org>
In-Reply-To: <20191003154533.590915454@linuxfoundation.org>
References: <20191003154533.590915454@linuxfoundation.org>
User-Agent: quilt/0.66
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

From: Jack Morgenstein <jackm@dev.mellanox.co.il>

commit 3eca7fc2d8d1275d9cf0c709f0937becbfcf6d96 upstream.

The cited commit introduced a double-free of the srq buffer in the error
flow of procedure __uverbs_create_xsrq().

The problem is that ib_destroy_srq_user() called in the error flow also
frees the srq buffer.

Thus, if uverbs_response() fails in __uverbs_create_srq(), the srq buffer
will be freed twice.

Cc: <stable@vger.kernel.org>
Fixes: 68e326dea1db ("RDMA: Handle SRQ allocations by IB/core")
Link: https://lore.kernel.org/r/20190916071154.20383-5-leon@kernel.org
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/infiniband/core/uverbs_cmd.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -3477,7 +3477,8 @@ static int __uverbs_create_xsrq(struct u
 
 err_copy:
 	ib_destroy_srq_user(srq, uverbs_get_cleared_udata(attrs));
-
+	/* It was released in ib_destroy_srq_user */
+	srq = NULL;
 err_free:
 	kfree(srq);
 err_put: